From the Rapture Fail website:
RaptureFail has been set up to allow people around the world to catalogue the failure of Harold Camping’s Rapture prophecy for the 21st of May 2011.
As Christians who take the Bible seriously we believe that “prophecies” like these demean the church’s witness in the world. The purpose of this site is to demonstrate very clearly (and to mock gently) that this is a false prophecy and that Harold Camping is a false prophet.
As 6pm on the 21st of May passes around the world, RaptureFail will show that the Rapture is not occurring by utilising the power of the internet and global user input. Everybody who participates in this project will be part of the undermining of this embarrassment to the Body of Christ.